The invention disclosed herein relates to a sign of the type in which indicia such as numerals indicating a price may be changed by scrolling webs in individual modules which are arranged adjacent each other. Ambient light may be relied upon for allowing reading of the indicia but usually the webs are back lighted.
It is often necessary to change pricing or other information that is readable from a sign. The sign disclosed herein is especially desirable for displaying the price of gasoline and, possibly, the name of the retailer such that this information can be seen from a great distance by automobile drivers. The sign is usually mounted at a substantial height near to the highway but remote from the station at which the gasoline is dispensed.
Signs in which webs containing indicia are scrolled to change the information which the sign is displaying are known. One such sign is described in U.S. Pat. No. 4,741,118. In this patent, the individual webs containing the indicia have their opposite ends wound on rolls which can be driven rotationally so that one roll pays out web and the other roll takes up web to locate a particular indicia in the display window of the sign. A group of webs are placed adjacent each other and their take-up rolls are journaled for turning on a common shaft. The shafts on which the take-up and pay-out roll for each web are journaled for rotation are driven by a single motor which is energized to rotate in one direction or the other when one or more webs is to be translated to change the indicia which are being displayed. A clutch is affiliated with each take-up roll. The electrical controls provide for starting the motor and engaging a selected one of the clutches when an indicia is to be changed. When that indicia reaches the display position in the viewing window of the sign, the clutch disengages. Because the drive motor and drive shafts are necessarily displaced from the web rollers in the design, the housing for the sign must be made substantially larger to accommodate these parts.
Another changeable scrolling sign is described in U.S. Pat. No. 3,255,541. In this patent the rolls on which the opposite ends of the web are wound are mechanically coupled by means of sprockets and a chain so they rotate together when one of the sprockets or gears is driven by a single motor. In this patent, the drive shafts for the rolls are coupled to the rolls through the agency of preloaded coil or torsion springs which are preloaded in a direction such that when driving power is discontinued the stored energy in the springs tends to rotate the rolls in a direction which imparts tension to the web extending between the rolls. In this patent and the patent discussed above, the drive motors for the rollers must be placed where they will not cast a shadow on the webs. As a result, the housing of the sign must be made larger so that the power can be displaced from the webs.